COSMOS 646

COSMOS 646 is an active satellite operated by GUKOS RVSN (Russia (CIS)), launched on 1974-04-23 from Plesetsk Cosmodrome, Russia on the Strela-1M launch. After more than 52 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 1,403 km and 1,484 km with an inclination of 74.0°. It travels at approximately 25,711 km/h (7.14 km/s), completing one full orbit every 115 minutes — that’s roughly 12.55 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is thousands of years. Orbital Radar tracks COSMOS 646 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

COSMOS 646 orbits at an average altitude of 1,444 km in the uppermost reaches of Low Earth Orbit. At this altitude, orbital decay is effectively zero without active deorbiting, and coverage footprints are significantly larger than lower LEO, though at the cost of higher latency. Within ±50 km of COSMOS 646’s average altitude, there are currently 539 active payloads and 332 tracked debris or rocket body fragments. With an inclination of 74.0°, COSMOS 646 passes over latitudes between 74.0°N and 74.0°S, covering most populated land masses in both hemispheres. This mid-inclination band balances global coverage with efficient launch energy requirements. Russia (CIS) operates approximately 1,553 active satellites in total, of which 482 share a similar altitude band with COSMOS 646.